OBJECTIVES: Although delayed bleeding after endoscopic procedures has become a problem, currently, there are no appropriate animal models to validate methods for preventing it. This study aimed to establish an animal model of delayed bleeding after endoscopic procedures of the gastrointestinal tract. METHODS: Activated coagulation time (ACT) was measured using blood samples drawn from a catheter inserted into the external jugular vein of swine ( RESULTS: Delayed bleeding was observed in three swine (75%) in the heparin-treated group, who had a maximum ACT of >
220 s before the start of continuous heparin administration. In the non-treated group ( CONCLUSION: An animal model of delayed bleeding after an endoscopic procedure in the gastrointestinal tract was established using a single dose of heparin and continuous heparin administration after confirming an ACT of 220 s.